1. Field of the Invention
The present invention relates to a reciprocating compressor, and in particular to a reciprocating compressor which is capable of simplifying an assembly process and improving assembly strength by constructing a reciprocating motor as one assembly and combining it with a compressing unit.
2. Description of the Prior Art
In general, a compressor is classified into a rotary compressor, a reciprocating compressor and a scroll compressor, etc. according to fluid compressing methods.
The reciprocating compressor compresses a fluid by a reciprocating motion of a piston by a reciprocating motor.
FIG. 1 is a sectional view illustrating the conventional reciprocating compressor.
The conventional reciprocating compressor includes a sealed casing 106 at which a suction pipe 102 and a discharge pipe 104 are connected; a motor unit 108 disposed in the casing 106 and generating a reciprocating motion force; a compressing unit 110 receiving the reciprocating motion force from the motor unit 108 and compressing a fluid; and a supporting unit 112 for supporting the motor unit 108 and the compressing unit 110.
The motor unit 108 consists of a cylindrical outer stator 114 fixed to the supporting unit 112; an inner stator placed so as to have a certain air gap from the inner diameter of the outer stator 114; a wound coil 118 wound inside the outer stator 114 and receiving power from the outside; and a magnet 120 placed between the outer stator 114 and the inner stator 116 with a certain interval and linearly reciprocated when power is applied to the wound coil 118.
As depicted in FIG. 2, in the outer stator 114, single bodies 128 respectively fabricated by laminating a certain number of thin lamination sheets are placed in the radial direction at regular intervals.
Because the single bodies 128 are placed at regular intervals, each space portion 121 in which a combining bolt 160 passes is formed between the single bodies 128. And, each magnet 120 is fixed at the outer circumference of a magnet holder 122 at regular intervals, the magnet holder 122 is connected to the piston 124 of the compression unit 110, and the piston 124 is connected to a spring sheet member 126.
The compressing unit 110 includes the piston 124 connected to the magnet holder 122 and performing a linear reciprocating motion; a cylinder 130 receiving the piston 124 so as to slide in/out and having a certain compression space; and a suction valve 134 installed at the front of the piston 124 and opening/closing a fluid channel 132 formed at the piston 124.
As depicted in FIG. 3, the supporting unit 112 includes a first frame 140 for supporting the cylinder 130; a second frame 142 combined with the first frame 140 and supporting the side of the outer stator 114 of the motor unit 108; a third frame 144 combined with the second frame 142, supporting the other side of the outer stator 114 and supporting the inner stator 116; and the first, second, third frames 140, 142, 144 are combined with each other by the combining bolt 160.
And, a first spring 146 for providing an elastic force in receding of the piston 124 is placed between the inner side of the first frame 140 and one side of the spring sheet member 126, and a second spring 148 for providing an elastic force in proceeding of the piston 124 for the compressing operation is placed between the side of the second frame 142 and the other side of the spring sheet 126.
The first frame 140 is inserted into the outer circumference of the cylinder 130 and includes a bolt combining groove 150 formed at the second frame combining portion in the circumferential direction.
In the second frame 142, a step portion 152 being inserted into the inner circumference of the first frame 140 is formed at one side, the other side is formed as a ring shape contacted tightly to the surface of the outer stator 114. And, the second frame 142 includes bolt through hole 162 formed in the circumference direction to pass the combining bolt 160 by being connected to the bolt combining groove 150 of the first frame 140.
The third frame 144 is combined with the inner stator 116, tightly contacted to the other side of the outer stator 114 and includes a bolt through hole 164 formed in the outer circumferential direction.
The bolt combining groove 150 of the first frame 104, the bolt through hole 162 of the second frame 142 and the bolt through hole 164 of the third frame 144 are combined with each other by the combining bolt 160, and the combining bolt 160 passes the space portion 121 of the outer stator 114.
The assembly process of a supporting portion 112 of the conventional reciprocating compressor will be described.
The cylinder 130 is inserted into the inner circumference of the first frame 140, the inner stator 116 is combined with the inner circumference of the third frame 144, the step portion 152 of the second frame 142 is combined with the inner circumference of the first frame 140, and the outer stator 114 is placed between the second frame 142 and the third frame 144. And, the bolt combining groove 150 of the first frame 104, the bolt through hole 162 of the second frame 142 and the bolt through hole 164 of the third frame 144 are respectively arranged on the same straight line, and the combining bolt 160 are inserted into them and fastened.
Herein, the combining bolt 160 passes the space portion 121 of the outer stator 114.
However, in the conventional reciprocating compressor, in assembly of the supporting portion 112, because the bolt combining groove 150 of the first frame 104, the bolt through hole 162 of the second frame 142 and the bolt through hole 164 of the third frame 144 are combined with each other by the one combining bolt 160 after being arranged on the same straight line, a precise process of each construction part is required to coincide the center of the bolt combining groove 150 with the center of the bolt through holes 162, 164, and accordingly a fabrication process is increased and the assembly process is intricate.
In addition, in assembly of the first, second and third frames 140, 142, 144, because the center of the piston 124 may not coincide with the center of the cylinder 30 due to a fabrication error of each construction part, herein, abrasion of parts occurs, noise occurs in the operation, and accordingly a compression efficiency is lowered.
In addition, concentrated stress acts on the bolt through holes 150, 162, 164 of each frame by the joint force of the combining bolt 160, the holes may be damaged in the operation.